1. Technical Field
This method relates to infrared welding of thermoplastic parts. Directed infrared welding provided for non-surface contact of the heat source with the work piece for applications where traditional welding techniques such as hot plate, electromagnetic body, vibratory or ultrasonic welding is not appropriate.
2. Description of Prior Art
Prior art devices of this type have relied on a number of different configurations to focus infrared energy source by focusing the energy to a desired area. Such techniques include general focus infrared welding in which a concentrated beam of infrared radiation is scanned on a surface to progressively raise the temperature of the radiated area, continuous heating by infrared sources and soddering by infrared energy, see for example U.S. Pat. Nos. 3,649,811, 4,725,716 and 5,113,479.
In U.S. Pat. No. 3,649,811 an elliptical or cylindrical reflector is used to channel a concentrated output of radiant energy having a relatively high flux density output which can be applied to a raised area of the heat sensitive work piece.
U.S. Pat. No. 4,725,716 is directed towards the use of infrared energy to solder components on electronic circuitry boards using a heat sink to absorb excess heat that would build up on adjacent components. The circuit board is momentarily positioned below an infrared source with a large heat sink directly therebelow.
A method of infrared heating on a continuous thermoplastic laminate is disclosed in U.S. Pat. No. 5,113,479 in which a source of infrared radiation is positioned within a directional reflector to restrict the area to be exposed on thus heated. The laminated web can have color stripes to absorb heat generated by the IR energy source, thus increasing efficiency and accuracy of the portions of the web to be heated.